On Sat, Oct 21, 2017 at 7:52 PM, Srinivas Pandruvada
<srinivas.pandruvada@xxxxxxxxxxxxxxx> wrote:
> Ev Kontsevoy reported that he can't see the presence of
> "/proc/sys/kernel/sched_itmt_enabled" on i9-7900x with Asrock x299
> Taichi system even if he enabled "Turbo 3.0" in the BIOS.
>
> The problem is that even if one core max is 200MHz more than others, the
> current implementation couldn't enumerate that with the way the system
> is configured.
>
> The system by default configured for legacy mode (no HWP or speed shift
> technology), in this mode only way we can enumerate via the mail box
> interface as implemented in this driver. We were planing to only use
> this driver for Broadwell, but we need to extend this because some
> Skylake system has same issue as Braodwell systems.
>
> On this system BIOS allows to change to HWP mode, where we expect that
> we can enumerate favored core with ACPI-CPPC. But on this system the
> core priority is 0xff for all cores in CPPC object. So this is not an
> option.
>
> Hence this change allows Skylake systems to be enumerate favored core
> similar to Broadwell in legacy mode.
Pushed to my review and testing queue, thanks!
>
> Reported-and-tested-by: Ev Kontsevoy <ev@xxxxxxxxxxxxx>
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
> ---
> drivers/platform/x86/intel_turbo_max_3.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/platform/x86/intel_turbo_max_3.c b/drivers/platform/x86/intel_turbo_max_3.c
> index 4f60d8e..d4ea018 100644
> --- a/drivers/platform/x86/intel_turbo_max_3.c
> +++ b/drivers/platform/x86/intel_turbo_max_3.c
> @@ -125,6 +125,7 @@ static int itmt_legacy_cpu_online(unsigned int cpu)
>
> static const struct x86_cpu_id itmt_legacy_cpu_ids[] = {
> ICPU(INTEL_FAM6_BROADWELL_X),
> + ICPU(INTEL_FAM6_SKYLAKE_X),
> {}
> };
>
> --
> 2.5.5
>
--
With Best Regards,
Andy Shevchenko
